Tool 01

Friis Link Budget

Estimate received power, path loss, antenna gains, and link margin for free-space RF links. Review sweep trends with graphs and CSV export.

Parameters

Enter transmit power, antenna gains, frequency, distance, and system losses. Use the sweep settings to compare how the selected variable changes the link budget.

Frequency

Distance

Tx Power

dBm

Tx Antenna Gain

dBi

Rx Antenna Gain

dBi

Additional Loss

Sweep Graph

Data Step (blank = Auto)

GHz

Start/end values must be positive. Custom Data Step applies to Linear X scale; Log X uses automatic logarithmic points.

X AxisY Axis

Reference Values

Frequency [GHz]: 10.000
Distance: 1.000 m
Tx EIRP: 10.00 dBm
Rx Chain Correction: 10.00 dB

Formulas

Wavelength

Calculate free-space wavelength from frequency.

\lambda = \frac{c}{f}

Free-space Path Loss

Calculate FSPL in dB from distance and wavelength.

FSPL_{dB} = 20\log_{10}\left(\frac{4\pi R}{\lambda}\right)

Displayed FSPL

Display FSPL as a negative value so it appears as a loss term in the link budget.

FSPL_{display} = -FSPL_{dB}

Received Power

Calculate received power by summing transmit power, antenna gains, path loss, and additional losses.

P_r = P_t + G_t + G_r + FSPL_{display} - L

FSPL is displayed as a negative value so it reads intuitively as a loss term in the link budget.